The present invention relates in general to inflatable dunnage bags for use in shipping freight by rail, ship, truck, aircraft and the like, and in particular to a new and useful air valve and coupling arrangement for an inflatable dunnage bag.
Known dunnage bags comprise an inner bladder of plastic, typically polyethylene, surrounded by several layers of reinforced paper. A valve arrangement is provided in the wall of the dunnage bag for facilitating inflation of the bag with air.
In use, a dunnage bag is placed in a space between cargo and inflated to firmly hold the cargo for transportation.
It is known to utilize a handle near the air valve for holding the valve while it is being inflated. See, for example, U.S. Pat. No. 4,073,389.
To inflate a dunnage bag, the coupling at the end of an air hose is normally manually pressed and held against the dunnage bag air valve. This simultaneously depresses a spring loaded valve member to open the valve, and seals the coupling between the air hose and the air valve. The air hose coupling must be firmly held against the valve during the entire inflation process to maintain this seal. See, for example, U.S. Pat. Nos. 4,146,069 and 4,146,070.
Since the dunnage bag air valve is often in an awkward position, and considerable force must be exerted to hold the air hose against the air valve, a metal air hose coupling has been developed which includes a sleeve that engages around the plastic stem of the dunnage bag air valve. Inwardly movable teeth are activated by a ring on the metal coupling to bite into the plastic valve stem, to hold the coupling to the stem. While this arrangement has been partly successful in maintaining a firm and sealed coupling between the air hose and the air valve, the coupling is not entirely secure and often falls from the valve during the inflation process. The coupling is also complex, heavy and expensive.
It is known to provide a mechanism for firmly holding an inflation coupling to a valve stem. See, for example, U.S. Pat. No. 3,087,518. A quick connect or bayonet type push and twist engagement between a cap and a container or container stem is also known. See, for example, U.S. Pat. No. 3,072,276. The use of a push and twist bayonet connection is also known in the field of air valves in general, from U.S. Pat. No. 3,536,117.
Nothing in the prior art, however, teaches a simple, inexpensive yet effective valve and coupling arrangement for a dunnage bag which easily and self-supportingly engages an air hose to the valve and, after the bag is inflated, easily and quickly disconnects the air hose.